package dzz.Week1;

import java.util.HashMap;
import java.util.Map;

/**
 * @author dzz   220230607
 */
public class LeetCode1_TwoSum {

    // 1. 暴力算法
    class SolutionFor {
        public int[] twoSum(int[] nums, int target) {
            int n = nums.length;
            for (int i = 0; i < n; i++ ) {
                for (int j = i + 1; j < n; j++) {
                    if (nums[i] + nums[j] == target) {
                        return new int[]{i,j};
                    }
                }
            }
            return new int[0];
        }
    }


    // 2. hash算法
    class SolutionHash {
        public int[] twoSum(int[] nums, int target) {
            Map<Integer, Integer> hashtable = new HashMap<Integer, Integer>();
            for (int i = 0; i < nums.length; i++) {
                if (hashtable.containsKey(target - nums[i])) {
                    return new int[]{hashtable.get(target - nums[i]),i };
                }
                hashtable.put(nums[i], i);
            }
            return new int[0];
        }
    }



}
